Automatic Weld Arc Monitoring System

ABSTRACT

A welding system including an arc monitoring, training, and control system is disclosed. The welding system includes a power supply, controller, and associated memory. When a weld is performed, the weld command and weld feedback parameters can be stored in the memory, along with associated alarm limit values. During subsequent welds, the input weld commands and actual feedback values can be compared to the established limits, and a fault signal provided to an operator or supervisor when the value exceeds the established limits. The fault signals can be used for training operators, as well as providing monitoring signals, and can be stored with weld data in a database for later analysis. In addition, collected weld data can be used to determine when to clean, repair, or replace consumables, including, for example, contact tips, wire drive liners, and drive rolls, and to monitor usage of wire and gas.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional application61/019,972 filed Jan. 9, 2008, which is hereby incorporated by referencein its entirety.

FIELD OF THE INVENTION

The present invention is directed to a method and apparatus formonitoring arc data in welding systems, and more specifically to awelding system including an internal arc monitoring system formonitoring weld data, training operators, and communicating resultantweld data to internal databases and external devices.

BACKGROUND OF THE INVENTION

As the level of automation has increased in mass production facilities,and the speed of welding operations has increased, it has becomeincreasingly important for management personnel to monitor and controlwelding parameters and processes to assure consistent and proper joiningof materials, and to ensure that completed welds fall withinpredetermined quality parameters.

To provide a high level of consistency in welds, semi-automatic,automatic, and robotic welding processes therefore typically includewelding programs or procedures that are preprogrammed for specificoperations. These programs, in theory, should provide consistent andrepeatable welds, irrespective of the experience level of the user.Experience has shown, however, that even in highly automatedapplications, welding parameters can and do vary after long periods ofuse, and in different environmental conditions. These variations can becaused by a number of factors, including, for example, variations in theparts to be welded, variations in motor and wire feed speed control overperiods of use, variations in gas flow over time, and variations in thedistance between a welding tip and the workpiece.

Increasingly, moreover, welding personnel on the factory floor arerelatively inexperienced and insufficiently trained to properly identifyand correct for these problems. In addition to providing predeterminedwelding procedures, therefore, it is also important for managementpersonnel to monitor weld and operator performance. Monitoring of theweld allows management personnel to analyze the welding process,identify problems, and make corrections before significant down time orwaste of material occurs.

To meet these needs, arc monitoring devices have been developed. Thesedevices are typically stand-alone units, connected external to thewelding power supply, and which include sensors for monitoring weldingparameters, such as current, voltage, and wire feed speed. These devicestypically provide a visual or audible signal when a welding feedbackparameter is outside of a predetermined range, providing a signal to theoperator or his or her supervisor that a fault has occurred. Monitoringand alarm data can be used to train personnel by providing an alarmsignal when a weld has veered outside of accepted parameters. This datacan also be used to make corrections during the welding process, and canbe stored for analysis.

While providing a valuable function, these devices, however, addsignificantly to the complexity and expense of a welding cellinstallation, require additional external wiring for the sensors, andincrease the overall size or footprint of the cell itself. Furthermore,because these devices require external sensors, often times, they do notprovide sufficiently accurate readings of actual weld parameters, andthey cannot provide all of the data necessary for properly monitoring aweld.

Additionally, because these devices are external to the welding systemitself, they cannot monitor wire feed motor power or other parametersthat are useful in analyzing both equipment failure and failures ordeterioration of consumables, such as contact tips, or in othercomponents such as wire feed liners and drive rolls. Furthermore, thesedevices cannot be used to monitor or to adjust the welding commandsduring a welding process, and therefore are not optimized for trainingpurposes, or for teaching operators to correct for problems encounteredduring a weld, and cannot correct for poor selection of weldingcommands. The present invention addresses these problems.

SUMMARY OF THE INVENTION

In one aspect of the invention, a welding system is provided. Thewelding system comprises a power supply for providing welding power, awire feed system for providing wire to a weld, and a weld parameterfeedback sensor for monitoring at least one of a current feedback, avoltage feedback signal, and a wire feed speed feedback signal. Acontroller is programmed to receive a welding command for driving thepower supply and the wire feed system, to monitor the welding commandand the weld parameter feedback sensor, and to selectively store thewelding command and the monitored feedback as a programmed weld when anoperator selectively saves the selected weld parameters.

In another aspect of the invention, the welding system includes aprogrammed weld that is accessible to a user to provide the weld commandsignal to control the power supply and the wire feed system. Thecontroller can be further programmed to include a limit corresponding tothe weld command signal, and to provide a fault signal when the selectedlimit is exceeded.

The controller can also be programmed to monitor the weld commandparameters and weld feedback parameters during a weld, to selectivelystore the weld command parameters and feedback parameters for a weld ofan acceptable quality, and to calculate the limits as a function of thestored weld command parameters and feedback parameters.

In yet another aspect of the invention, the processor is furtherprogrammed to store a sequence of programmed welds as a programmed part,and to provide access to a user to selectively retrieve the programmedpart and to provide a command to weld the part. The processor can befurther programmed to associate a user with a selected limit. Theprocessor can further be programmed to associate an operator-suppliedtime with a weld to be performed, and to allow an operator to designatea plurality of sequential welds to designate a programmed part.

In another aspect of the invention, a method for monitoring a qualitylevel of a weld procedure is provided. The method comprises performing aweld of an acceptable quality and storing a weld command parameter and aweld feedback parameter corresponding to the weld, and associating afault limit with at least one of the weld command parameter and the weldfeedback parameter, and monitoring a corresponding weld commandparameter and a corresponding weld feedback parameter during asubsequent weld, and comparing the corresponding weld command parameterand the corresponding weld feedback parameter to the fault limits duringthe weld. A fault alarm signal is provided when the weld commandparameter exceeds the fault limit. The weld command parameter cancomprise at least one of a voltage command, a wire feed speed command,and an inductance command, and the weld feedback parameter comprises atleast one of a voltage feedback, a current feedback, a wire feed speedfeedback, and a weld time feedback.

In still another aspect of the invention, the method can comprise thestep of associating a user with the limits. A second weld of anacceptable quality can also be stored, along with a weld commandparameter and a weld feedback parameter corresponding to the secondweld. The weld command and the second weld command can be stored assequential welds in a programmed part.

In another aspect of the invention, the method comprises the step ofreceiving a user-selected weld time, and the step of monitoring acorresponding weld command parameter and a corresponding weld feedbackparameter during a subsequent weld further comprises monitoring theuser-selected weld time, and ending the subsequent weld when the weldtime is exceeded.

In yet another aspect of the invention, a method for monitoring aquality level of a weld procedure is provided. The method comprisesperforming a weld, determining whether the weld is of an acceptablequality, storing a weld command parameter and a weld feedback parametercorresponding to the weld as a weld program when the weld is of anacceptable quality, and accessing the weld program to provide a weldcommand parameter for a subsequent weld.

The method can also comprise the steps of performing a second weld,determining whether the second weld is of an acceptable quality, storinga weld command parameter and a weld feedback parameter corresponding tothe second weld as a second weld program when the weld is of anacceptable quality, selectively linking the weld program and the secondweld program as a part program, and accessing the part program toprovide a weld command parameter for a subsequent weld comprising theweld program and the second weld program.

These and other aspects of the invention will become apparent from thefollowing description. In the description, reference is made to theaccompanying drawings which form a part hereof, and in which there isshown a preferred embodiment of the invention. Such embodiment does notnecessarily represent the full scope of the invention and reference ismade therefore, to the claims herein for interpreting the scope of theinvention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a block diagram of a welding system capable of use in thepresent invention;

FIG. 2 is screen shot illustrating a main screen for selecting optionsin the welding system of FIG. 1;

FIG. 3 is a screen shot illustrating a weld program set-up screen foruse in the welding system of FIG. 1;

FIG. 4 is a flow chart illustrating operation of the welding system ofFIG. 1 in a set-up mode;

FIG. 5 is a screen shot illustrating a post-weld set-up screen providingan option of storing a weld;

FIG. 6 is a screen shot illustrating a part set-up function for use inthe welding system of FIG. 1;

FIG. 7 is a screen shot of a weld monitor configuration screen for usein the welding system of FIG. 1;

FIG. 8 is a screen shot of a weld data configuration screen for use inthe welding system of FIG. 1;

FIG. 9 is a screen shot of a user interface illustrating displaying theresults of an on-going weld during arc monitoring;

FIG. 10 is a flow chart illustrating the arc monitoring mode ofoperation of the weld system of FIG. 1;

FIG. 11 is a screen shot illustrating a display of weld data after aweld;

FIG. 12 is a screen shot illustrating a database of weld data;

FIG. 13 is a screen shot illustrating weld details of a selected weldfrom the weld data screen of FIG. 12.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the Figures and more particularly to FIG. 1, anexemplary welding system 10 is shown. The welding system 10 includes ahousing 11 containing a power supply 12, a controller 16, and acommunications system 30. The controller 16 can include one or moremicrocontroller, microprocessor, digital signal processor, or otherprogrammable controller, along with an internal or external memorycomponent 18, capable of storing welding programs and proceduresspecified by the user. Bidirectional communications between thecontroller 16 and external devices are provided through thecommunications system 30, preferably through a serial communicationslink such as DeviceNet, Profibus, RS-232 or other communicationssystems, or through a network communications device such as an Ethernetconnection or other wired or wireless communication devices. Thecontroller 16 may also be connected to a user interface 32, which can bemounted in the housing 11, or provided external to the housing 11 andwelding system 10, and can include a user display and input devices,such as keys, switches, joysticks, analog or digital potentiometers, orother devices to provide information to and receive information from anoperator or user of the welding system 10. Alternatively, or in additionto the communications devices discussed above, individual analog anddigital inputs and outputs could be directly connected to the controller16 either in conjunction with, in place of, or as part of thecommunications systems 30 discussed above. The power supply 12 can be aconstant voltage power supply or a constant voltage/constant currentpower supply, and preferably includes pulsing capabilities.

Referring still to FIG. 1, the controller 16 is further connected toexternal welding components including a wire feed system 20, and a gasvalve 23. The wire feed system 20 includes a motor 19 that drives wirethrough drive rolls and a liner to a torch or gun 13 including a contacttip. The gas valve 23 can be either an on/off valve, a metered valvecontrolled by controller 16, or can include a separate or integral flowmeter.

Optionally, the welding system 10 can be provided in a welding cell,which can include, for example, flexible or hard automation components,such as a welding robot 21, a programmable logic controller (PLC) 27,and fixtures 29. The fixtures 29 can include devices such as clamps formaintaining a workpiece 14 in position during a weld, and preferablyalso include sensing devices, such as devices for providing a signal tothe controller 16 when associated clamps either open or close, andproximity sensors for sensing a position of the workpiece 14 in thefixture 29 or a position of a welding torch approaching the workpiece14. Additionally, a series of light emitting diodes, laser diodes, orother lighting elements can be provided in the fixture either toilluminate an area to be welded for the operator, or to provide anindicator to the operator. The indicator can, for example, indicatewhich in a series of welds is to be performed, providing a sequence forthe operator. Lighting and other visual aids can also be used toindicate when a welded part is complete. Audio-producing devices, suchas buzzers and horns, can also be associated with the fixture to providea signal to an operator or supervisor when a weld is complete, when anerror has occurred, or in various other situations. These devices can beconnected directly through the communications system 30, or through anexternal device such as the PLC 27, robot 21, a computer system, orother controller.

The welding system 10 can be used in various modes of operation,including both semi-automatic and automatic modes of operation. Weldcommand parameters can be stored as pre-programmed weld procedures inmemory 18, as discussed more thoroughly below, or provided to the weldsystem 10 during a weld through communications system 30. In asemi-automatic mode, for example, an operator provides a trigger signalto the controller 16 from a hand held wire feed gun or torch, and caneither use pre-programmed command levels, or by varying voltage and wirefeed speed values during the weld. In the automatic mode, an externaldevice, such as a robot controller associated with robot 21 or the PLC27 provides a signal to the controller of the welding system 10 to startthe weld. Again, weld parameter commands can be retrieved from memory18, or be provided from the robot 21, PLC 27, or another external devicethrough communications system 30.

In operation, the controller 16 receives a trigger signal as describedabove and commands the power supply 12 to provide welding current andvoltage to start an arc at the workpiece 14. Command levels forcontrolling the weld can be set and stored internally in memory 18, orcan be received from the external components, such as robot 21 and PLC27, or other controllers or computers as discussed above, either in theform of analog or digital control signals. Based on the commands, thecontroller 16 also commands the wire feed system 20 to drive fillermetal from the motor 19 to a contact tip in torch 13, providing wire tothe weld at the workpiece 14. The controller 16 also controls the gasvalve 23 to selectively provide shielding gas to the weld. Depending onthe type of gas valve used, the controller 16 can provide a simpleon/off signal, or control the level of flow from the valve 23.

During operation, the controller 16 receives feedback from a voltagesensor 26, a current sensor 28, and a wire feed speed sensor ortachometer 24, and can also optionally monitor gas flow through a gasflow sensor associated with the gas valve 23. The feedback data is usedby the controller 16 to control the power supply 12, wire feed system20, and gas valve 23. The feedback and command data, moreover, can beused in a set-up mode to determine weld parameter values for a knowngood weld, which can then be stored as a weld program in the memory 18,as described below. The weld parameters determined during set-up can befurther used to monitor the arc during a weld and to provide weld datato supervisory or other personnel through the communications system 30,and selectively to provide visual or audio signals to a supervisor oroperator when fault conditions are encountered.

Referring now to FIG. 2, a main display screen 35 for a weld monitor andtraining device constructed in accordance with the present invention isshown. The main display can be provided on a user interface 32, from adisplay interface associated with a PLC 27 or robot 21, or from acomputer or other device in communication with the communications system30. At the main display screen, a user can select between a Weldfunction (60; FIG. 9), a Weld Edit function, a Weld Program Set-Upfunction (34, 35; FIGS. 3 and 5), a Part Set-Up function (52; FIG. 6), aWeld Monitor Configuration function (36; FIG. 7), a Weld DataConfiguration function (58; FIG. 8), and a Weld Data Access function(88; FIG. 12). Together, these selected functions allow a user to weld aspecific part or program; to establish a “good” or “gold standard”program for monitoring the weld on a part; to edit existing storedprograms; to establish a sequence of welds for welding a part or job; toconfigure selected monitoring functions; to establish statisticalanalysis parameters for a weld; and to review specific weld parametersand fault data for a given weld. Although a series of display screensare shown here, it will be apparent that these displays are by way ofexample only, and that the functions described and data display could beprovided in any number of ways.

Referring now to FIGS. 3-5, display screens and a flow chart are shownto illustrate the Weld Set-Up function, in which the welding system 10is used to establish a welding procedure based on a known good or “goldstandard” weld. Referring first to FIG. 3, on entry to the Weld ProgramSet-Up function, a display 34 is provided through which a user can namea weld program, using either numerical indicators, as shown here, oralphanumeric characters. The user can then select to use internalsignals, e.g. establishment of the command welding parameters frommemory 18 or from a display 32 or other component associated with thewelding system 10, or to receive welding commands from an externalsource such as a PLC 27 or robot 21, human machine interface, externalcontroller, teach pendant, or other component through the communicationssystem 30 (FIG. 1). As shown here, the established program is a GMAW(MIG) welding program, and the identified commands are voltage, wirefeed speed, and optionally, an inductance command. Other parameters,such as an adjustable arc delay time, which allows a user to select amaximum time period for an arc to start as determined based on currentfeedback, voltage feedback or both, can also be established. Monitoringalarm limits, either as a max and min value or a percentage value ofboth the actual feedback and command weld parameters, including voltage,wire feed speed, current, and inductance can optionally be establishedprior to the weld set-up. Although a GMAW weld set-up is shown anddescribed, it will be apparent that the present invention is not limitedto weld systems of this type, and could also be used with other types ofwelds, including, for example, pulsed MIG, and that the appropriatecommands and feedback would vary depending on the type of weldperformed.

Referring now to FIG. 4, after the weld parameters are established, theuser can weld a part to establish a “gold standard weld”, as provided inthe flow chart shown here. Initially, in process block 40, an operatoroptionally sets limits for all of the weld parameters or individuallimits for selected weld parameters, which, as discussed above, caninclude command levels for the welding power system, including a voltagecommand, a wire feed speed command, and a trim command, and can alsoinclude feedback parameters, including an actual voltage, an actual wirefeed speed, an actual weld time, an actual weld current, or otherparameters. The limits can be specified in terms of units, as, forexample, in terms of volts, amps or inches per minute, but arepreferably, as shown in FIG. 4, established as a percentage value foreach selected parameter. Each of these limits, moreover, can beestablished individually for each selected weld parameter, and can bevaried from weld program to weld program, to provide a customizedprogram for each weld that is tailored specifically to an application.Alternatively, as discussed below, limits can be associated with anindividual operator for training or other purposes.

After the limits are established as described above, in process block 42the operator selects wire feed, voltage, and, optionally, inductance ortrim command values, and performs one or more welds (process block 44)at varying selected weld parameters. During the set-up process, thecontroller 16 monitors the wire feed, voltage, and current feedback fromsensors 24, 26, and 28, respectively, and, based on this feedback,samples and stores actual voltage, current, and wire feed speed dataacquired during the weld in the memory 18, along with the overall weldtime between the establishment of an arc, and the end of the arc. If theuser is providing the commands from an external source, such as a PLC 27or robot 21, the command wire feed, voltage and inductance values arealso stored, and in the case of analog input values, can also be sampledat a selected rate.

Referring now also to FIG. 5, after the weld is complete, a displayscreen 36 displays the weld command values and actual weld parameters.The operator can change the command welding parameters, as shown by icon38, and perform an additional weld. Alternatively, when the operator issatisfied with a weld, in process block 46, the operator provides asignal to the controller 16 through either the user interface 32 or froman external device through communications system 30, indicating that theparameters from the selected weld are to be stored as the designatedweld program. As shown here in FIG. 5, for example, a “store weldprogram” icon 37 or other selectable option can be provided on thedisplay screen. In response to the signal from the operator, thecontroller 16 stores the selected voltage and wire feed speed commandvalues, along with the average actual wire feed speed, voltage, andcurrent values of the weld, and the overall arc time (process block 48).If limits have been selected, the controller 16 can then calculate theupper and lower limits for each weld parameter stored based on theselected limits for each of these parameters. The saved program can bestored in memory 18 and/or at an external device with the identifyingname or number for later retrieval. The upper and lower limits can bestored with the average values, as shown, or re-calculated whenever aprogram is selected for operation. Alternatively, as discussed below,the command and feedback values for the weld can be stored withoutlimits, and upper and lower limits can be established and associatedwith a particular operator, with a particular weld, or with a sequenceof welds defining a part or job.

Referring again to FIG. 2, after the weld program is stored in memory,the operator can optionally access the saved program through a displayor other methods, using either the user interface 32 or through anexternal device, retrieve the program data and edit the individual weldparameters and limits. Referring now also to FIG. 6, the user can alsospecify a series of sequential welds to be used in welding a specificpart or job, by selecting the Part Set-Up function 52. As shown here, aseries of weld programs can be specified in an order, and a weld countprovided to indicate the number of individual welds that are expected toweld a selected part or job. Based on the weld count, arc starts and/orends can be monitored to verify that all of the welds in a sequence havebeen completed. A numeric or alphanumeric name, and a selected arc starttime can also be associated with the individual part. These parameterscan then be stored in memory by activating, for example, the save particon 54. Alternatively, a series of welds could be welded as describedabove, and an order specified during the set-up procedure. For example,a user could specify a number of welds for a part, and sequentially savethe welds until a part is specified.

Referring now to FIG. 7, from a Weld Monitor Configuration screen 56,the operator or a supervisor can also selectively activate a program orpart to be welded, and monitoring functions, including an arc monitoringfunction that compares the weld parameters against the limit values, anda weld count function. The operator can also set and enable limits, andenable and define fault signals. Additionally, for tracking ormonitoring purposes, a specific operator can be identified, andindividual monitoring limits can be defined for the operator. As shownhere, for example, the name of the operator can be stored at thebeginning of a shift, for example. Additionally, the min and max limitsfor both actual and command weld parameters can be specified to providethe alarm limits that will be activated during any selected weld. Theseindividual limits can also be selectively enabled and disabled.Optionally, the operator or supervisor can also specify the type offault indicator, either as a single indicator for all of the weldparameters, as shown here, or individually for each specific weldparameter. For example, when an alarm condition occurs, the operator canelect to provide a visual or audible display to the operator or tosupervisory personnel. An alarm limit could also be used to shut downthe welding system, prompting the operator to start over with a newpart, or to send a notification to a supervisor, through, for example, apager system, email, cellular telephone, or other communication methodsaccessed, for example, through the communications system 30. The optionto select a timed weld, in which the user specifies an overall time forthe weld process, an amount of weld material or weld wire to bedeposited, can also be provided.

In addition, the Weld Monitor Configuration screen 56 allows the user toactivate “programmed commands”. When “programmed commands” is activated,the controller 16 controls the weld parameter commands, preventing theoperator from supplying external commands or otherwise modifying theinput commands. This function, for example, is useful when an operatoris inexperienced, and can also be used as a training tool, allowing anoperator to view the weld as controlled by the power supply. After theoperator is comfortable with the weld, the programmed commands can bedeactivated, and the operator allowed to provide a weld command signalthat is monitored within selected arc monitoring limits. These limits,moreover, can be varied depending on the experience level of the user.Referring again to FIG. 7, a “restore commands” function can also beprovided. When this function is activated, the weld command parametersfor a specific weld program or part can be restored to their initialstored values, either at the power supply 12, or through transmission toan external device through communication system 30. This function isuseful, for example, to restore command values after a power failure, orafter parameters have been edited out of range, to reinstate the knowngood values. After the configuration is established through screen 56, auser can store the data to memory by activating icon 59.

Referring now to FIG. 8, a Weld Data Configuration screen 58 can also beprovided to allow a user to select sampling rates for data acquisitionfor the voltage, wire feed speed, and current feedback. Sampling ratescan also be associated with weld command values, such as analog commandsignals received from an external source such as a robot 21.Additionally, the user can select a number of welds, or alternatively, atime frame for calculating averages for each of these parameters. Again,these selected analysis parameters can be saved by activating icon 61.

Referring now to FIGS. 9 and 10, a weld display screen 60 that displaysweld data during the weld while arc monitoring is enabled is shown alongwith a flow chart illustrating use of the arc monitoring system. Whenthe arc monitor is enabled, in operation, the controller 16 monitors theactive weld program or part (process block 50) and monitors eithercurrent feedback from the sensor 28 or a combination of current andvoltage feedback from sensor 26 to determine whether an arc start hasbeen achieved, and a weld has been started (process block 52). Once anarc is established, the controller 16 stores a date and time stamp inmemory 18, retrieves the weld parameter limits and alarm enable/disabledata for the selected program from memory 18 (process block 54), andmonitors the welding parameters, accumulating averages and minimum andmaximum values for the actual weld voltage, weld current, and wire feedspeed, and accumulating weld time (process block 56). Optionally, thecontroller 16 can also calculate a run-in time as a function of the timebetween the start of the wire feed motor, and the arc start time. Afterarc start, the controller monitors each of the parameters to determinewhether they fall outside of the established limits (process block 58)and, if a parameter falls outside of the established limits, and thealarm for that parameter is enabled, the controller 16 creates an alarm(process block 60). The alarm, for example, can be provided byhighlighting a weld parameter that has exceeded the limit on a welddisplay, as shown by the error in bold in FIG. 9, or through an externaldevice connected to the welding system, such as a light or buzzer. Thecontroller 16 continues to monitor data until the weld ends (processblock 62). When the weld count function is activated, the processor 16can also increment a weld counter (process block 64). The weld data,approximate time and location of an alarm condition, and associated weldnumber or count, can all be stored in memory 18 and/or communicated toan external device through communication system 30.

Referring still to FIG. 10, and now also to FIGS. 1 and 11, at the endof the weld, the controller 16 calculates the overall weld time, averageactual wire feed speed, average actual weld voltage, and average actualweld current values, and displays these values on Weld screen 86. Basedon this data, the controller 16 can also calculate the amount of wireused during the weld, as a function of the wire feed speed and overalltime of the weld (process block 64). Other process parameters, includinggas usage, could also be calculated. This acquired data, along with anyalarm limits encountered during the weld, can be written to a display,as shown in FIG. 11, forwarded to a remote device through thecommunications system 30, stored in local memory 18, or any combinationof these options (process block 66). Additionally, using weld time data,proximity sensor data, weld count data, and optionally, travel speeddata from a robot or PLC, an approximate location of the alarm conditioncan be determined and stored in memory 18 or communicated throughcommunication system 30.

Referring now to FIGS. 2 and 12, stored weld data can be accessed by auser by selecting the Access Weld Data function from the main menu (FIG.2.), which leads to the Weld Data Screen 88 of FIG. 12. Here, datarelated to the welds performed on the welding system 10 are stored alongwith part or weld name, operator name, a date, and a time stamp. Byselecting an individual weld in the database of FIG. 12 using icon 89,the user can access the Weld Detail data of FIG. 13. As shown here, weldidentification and time stamp data is stored here with correspondingweld times, weld counts, average actual and command data for each of theparameters of the specific weld, and an average for the selected weldover a selectable number of welds. A listing of the faults that occurredduring the weld is also provided, and optionally, other weld data, suchas average or instantaneous motor power or current data, motor voltagedata, number of short circuits in a weld, etc. Additionally, consumabledata, such as wire usage and gas usage, can be determined and displayed.Acquired data can also be used to predict consumable life end. Forexample, motor current, voltage, and power parameters, and particularlychanges in motor parameters, can be used to evaluate wear on contacttips in the wire feed system 20, as well as wear in the liners and driverolls in the wire feed system. Changes in voltage feedback can also bemonitored and used to evaluate and troubleshoot problems in secondarygrounding and cables.

Although not shown here, as discussed above, to provide sufficient datato identify weld faults in specific parts and to troubleshoot problemswith the weld and equipment, location of the weld fault can bedetermined, for example, from fixture clamp and sensor data, travelspeed, and other identifying data. Alternatively, or in addition to thedatabase shown, a stream of data including weld data, weld time,proximity sensor data indicating, for example, the last sensor trippedand other weld, time and location sensor data can be communicatedthrough the communications system 30 to an external device such as a PLC27, a networked computer, or other data storage device.

The present invention therefore provides a highly flexible system thatprovides a number of significant improvements over prior art arcmonitoring systems. First, the arc monitoring system is provided withinthe welding power source, and uses the internal sensing components ofthe power source, thereby limiting the need for external sensors andexternal cabling, and reducing the footprint of the welding equipment inthe weld cell. The system, therefore, is significantly easier to connectin a welding cell than prior art systems.

Additionally, because the arc monitoring system of the present inventionreceives weld command data, including, for example, voltage, wire feedspeed, and inductance command input from an operator to drive the powersource, command input levels can be monitored in addition to feedbacklevels. As a result, the commands provided by an operator, whether froma handheld system, robot, or PLC, can be monitored, and an alarm signalgenerated when the command levels are out of an expected or acceptablerange.

The command level limits and fault data, moreover, can be used forimproving training of the operator, and also in troubleshooting externalequipment, and restoring commands to a useable level. As a trainingtool, for example, the power supply could initially be set to controlthe weld using a stored weld program, and the operator could observe theweld in process while welding. After observing the weld a number oftimes, the operator can be allowed to control the weld within definedlimits, as described above. The arc monitor can either monitor thecommand signals, the actual feedback signals, or both. Alarm signals canbe generated when either the command values or the actual feedbackvalues extend outside of a selected range of values. As the operatorimproves, the limits can be extended, and additional autonomy forcorrecting weld problems can be given to the operator.

Additionally, because the command values for a predetermined “good weld”are stored in the memory 18 of the weld system 10, the command levelscan be recalled and either controlled directly by the weld system 10 orsent to an external device to restore an acceptable command level. Thisfunction, for example, is useful when the commands provided by anexternal device are out of range, either due to an operator error, or toa power or other system failure, and is particularly important inrestoring usable welding conditions during automated welding processes,which could otherwise result in significant down time or material loss.

Additionally, because both weld command and feedback values can bemonitored and stored, the relationship between the command and resultantfeedback data can be analyzed to determine appropriate changes to theweld process due to changes in environmental conditions, time ofoperation, and other factors. The data can also be used to train andevaluate operators, as discussed above, for evaluating consumable usage,and for troubleshooting the system when weld problems occur.

Although a number of user-accessible screens are described above, itwill be apparent that access to the various functions described can belimited through the use of password protection, RFID tokens, digital ormechanical key systems, or other means. For example, one level ofsecurity may be provided to allow access to the weld monitorconfiguration, while a second level of security could be used to provideaccess to the weld acquisition data. Access to weld set-up and weldediting functions might also be limited, for example, to specificsupervisory personnel. Various levels of security could be provided tovary access to individual screens or to individual data on the variousscreens.

It should be understood that the methods and apparatuses described aboveare only exemplary and do not limit the scope of the invention, and thatvarious modifications could be made by those skilled in the art thatwould fall under the scope of the invention. For example, although apart set-up system is described in which segments of a weld are definedas individual programs, and a sequence of welds is defined to provide apart or job, it will be apparent that a part or job could be welded andstored as described above with reference to the weld set-up. Here,individual segments of a weld could be defined by proximity sensors orclamp sensing, by input from an operator through an interface, or invarious other ways.

Furthermore, while a specific set of screens is described above, it willbe apparent that the functions described could be implemented in anumber of different ways. Additionally, although specific data types aredescribed with reference to each of the screens described above, it willbe apparent that the data could be configured in any number of ways.

To apprise the public of the scope of this invention, the followingclaims are made:

1. A welding system comprising: a power supply for providing weldingpower to a weld; a wire feed system for providing wire to the weld; aweld parameter feedback sensor for monitoring at least one of a currentfeedback, a voltage feedback signal, and a wire feed speed feedbacksignal from the weld; and a controller programmed to receive a weldingcommand for driving the power supply and the wire feed system, tomonitor the welding command and the weld parameter feedback sensor, andto selectively store the welding command and the monitored feedback as aprogrammed weld when an operator selectively saves the selected weldparameters.
 2. The welding system of claim 1, wherein the programmedweld is accessible to a user to provide the weld command signal tocontrol the power supply and the wire feed system in a subsequent weld.3. The welding system of claim 1, wherein the controller is furtherprogrammed to include a limit corresponding to the weld command signal,and to provide a fault signal when the selected limit is exceeded. 4.The welding system of claim 1, wherein the controller is furtherprogrammed to monitor the weld command parameters and weld feedbackparameters during a weld, to selectively store the weld commandparameters and feedback parameters for a weld of an acceptable quality,and to calculate the limits as a function of the stored weld commandparameters and feedback parameters.
 5. The welding system of claim 1,wherein the processor is further programmed to store a sequence ofprogrammed welds as a programmed part, and to provide access to a userto selectively retrieve the programmed part and to provide a command toweld the part.
 6. The welding system of claim 3, wherein the processoris further programmed to associate a user with a selected limit.
 7. Thewelding system of claim 1, further comprising a communications systemproviding communications between the controller and an external device,and wherein the external device comprises at least one of a robot, aprogrammable logic controller, and a computer, and wherein the externaldevice provides the welding commands.
 8. The welding system of claim 1,wherein the processor is further programmed to associate anoperator-supplied time with a weld to be performed.
 9. The weldingsystem of claim 1, wherein the processor is further programmed to allowan operator to designate a plurality of sequential welds to designate aprogrammed part.
 10. A method for monitoring a quality level of a weldprocedure comprising: performing a weld of an acceptable quality andstoring a weld command parameter and a weld feedback parametercorresponding to the weld; associating a fault limit with at least oneof the weld command parameter and the weld feedback parameter;monitoring a corresponding weld command parameter and a correspondingweld feedback parameter during a subsequent weld; comparing thecorresponding weld command parameter and the corresponding weld feedbackparameter to the fault limits during the weld; and providing a faultalarm signal when the weld command parameter exceeds the fault limit.11. The method as recited in claim 10, wherein the weld commandparameter comprises at least one of a voltage command, a wire feed speedcommand, and an inductance command.
 12. The method as recited in claim10, wherein the weld feedback parameter comprises at least one of avoltage feedback, a current feedback, a wire feed speed feedback, and aweld time feedback.
 13. The method as recited in claim 10, furthercomprising the step of associating a user with the limits.
 14. Themethod as recited in claim 10, further comprising the steps ofperforming a second weld of an acceptable quality and storing a weldcommand parameter and a weld feedback parameter corresponding to thesecond weld, and storing the weld command and the second weld command assequential welds in a part.
 15. The method as recited in claim 10,further comprising the step of receiving a user-selected weld time, andwherein the step of monitoring a corresponding weld command parameterand a corresponding weld feedback parameter during a subsequent weldfurther comprises monitoring the user-selected weld time, and ending thesubsequent weld when the weld time is exceeded.
 16. The method asrecited in claim 10, further comprising the step of storing the weldfeedback parameters during the weld.
 17. The method as recited in claim10, further comprising the step of incrementing a weld count when eachsubsequent weld is completed.
 18. The method as recited in claim 10,further comprising the step of providing a user-selectable sampling ratefor sampling the weld feedback.
 19. A method for monitoring a qualitylevel of a weld procedure comprising: performing a weld with a weldingpower source; evaluating whether the weld is of an acceptable quality;and storing a weld command parameter and a weld feedback parametercorresponding to the weld as a weld program in a memory component of thewelding power source when the weld is of an acceptable quality.
 20. Themethod as recited in claim 19, further comprising the step of accessingthe weld program to retrieve the weld command parameter to control thepower source for a subsequent weld.
 21. The method as recited in claim19, further comprising the step of providing an upper and a lower limitfor the weld command parameter, and for selectively allowing an externalweld command parameter, wherein the weld command parameter is comparedto upper and the lower limits, and an alarm is generated when theexternal weld command parameter exceeds at least one of the upper andthe lower limits.
 22. The method as recited in claim 19, furthercomprising the steps of: performing a second weld; determining whetherthe second weld is of an acceptable quality; storing a weld commandparameter and a weld feedback parameter corresponding to the second weldas a second weld program when the weld is of an acceptable quality;selectively linking the weld program and the second weld program as apart program; and accessing the part program to provide a weld commandparameter for a subsequent weld comprising the weld program and thesecond weld program.